Bi-phased on-off keying (ook) transmitter and communication method

ABSTRACT

An on-off keying (OOK) transmitter and communication method are provided. The OOK transmitter may include a data encoder configured to encode input data into a transmission sequence, a pulse shaper configured to generate pulses based on the transmission sequence, a bi-phase controller configured to generate a control signal to control a random change in phase, between two phases, of a carrier based on the transmission sequence, a bi-phased switch configured to randomly change a phase of the carrier generated by a voltage-controlled oscillator (VCO), based on the control signal, and a power amplifier (PA) configured to generate a transmission signal based on the generated pulses and the carrier with the randomly changed phase. The PA may be a bi-phasing PA, and the bi-phased switch may be included in the bi-phasing PA.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a Continuation application of U.S. application Ser.No. 15/016,566, filed Feb. 5, 2016, which claims the benefit under 35USC 119(a) of Korean Patent Application Korean Patent Application No.10-2015-0032951 and Korean Patent Application No. 10-2015-0110586,respectively filed on Mar. 10, 2015 and Aug. 5, 2015 in the KoreanIntellectual Property Office, the entire disclosures of which are allincorporated herein by reference for all purposes.

BACKGROUND

1. Field

One or more embodiments relate to a bi-phased on-off keying (OOK)transmitter and communication method.

2. Description of Related Art

As only an example, a wearable device based on a wireless body areanetwork (WBAN) may be attached to a human body, and may wirelesslycommunicate with a neighboring mobile device or a sensor attached to thehuman body. To increase a period of time during which the wearabledevice can operate, e.g., without a burden of a battery charge, atransceiver may be implemented with a low complexity and designed tooperate at low power. For example, an ultra low power radio frequency(RF) structure and a transceiver having a low modulation complexity of amodem may be available. As another example, an on-off keying (OOK)transceiver capable of recovering data by detecting an envelope insteadof using phase information of a received carrier may be used in such lowpower communication in a WBAN.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is the Summaryintended to be used as an aid in determining the scope of the claimedsubject matter.

One or more embodiments provide an on-off keying (OOK) transmitterincluding a data encoder configured to encode input data into atransmission sequence, a pulse shaper configured to selectively generaterespective pulses based on each of plural bits of the transmissionsequence, a bi-phase controller configured to generate a control signalto control a random change in phase, between two phases, of a carrierbased on a periodicity of elements in the transmission sequence, abi-phased switch configured to randomly change a phase of the carrierbased on the control signal, the carrier being generated by avoltage-controlled oscillator (VCO), and a power amplifier (PA)configured to generate a transmission signal based on the generatedpulses and the carrier with the randomly changed phase.

The bi-phased switch may be configured to randomly change the phase ofthe carrier between 0 degrees and 180 degrees.

The data encoder may be configured to encode the input data into pluralpredetermined sequence patterns.

The bi-phase controller may generate the control signal so as to changethe phase of the carrier at least once during transmission of each ofthe plural encoded sequence patterns of the transmission sequence.

The bi-phase controller may be configured to adjust the control signalso as to initiate plural phase changes of the carrier during atransmission of an encoded sequence pattern of the transmissionsequence.

The OOK transmitter may further include a first buffer configured tobuffer the carrier generated by the VCO, to reduce effects of thegenerated control signal on a frequency of the carrier, before thecarrier is provided to the bi-phased switch.

The OOK transmitter may further include a second buffer configured tobuffer the carrier with the randomly changed phase, to reduce effects ofoperations of the PA on the VCO, before the carrier with the randomlychanged phase is provided to the PA.

The PA may be a bi-phasing PA, with the bi-phased switch being includedin the bi-phasing PA.

One or more embodiments provide an on-off keying (OOK) transmitterincluding a data encoder configured to encode input data into atransmission sequence, a pulse shaper configured to generate pulsesbased on the transmission sequence, a bi-phase controller configured togenerate a control signal to control a random change in phase, betweentwo phases, of a carrier based on a periodicity of elements in thetransmission sequence, and a bi-phasing power amplifier (PA) configuredto randomly change a phase of the carrier based on the control signal,and to generate a transmission signal corresponding to the generatedpulses and the carrier with the randomly changed phase, the carrierbeing generated by a voltage-controlled oscillator (VCO).

The bi-phasing PA may be configured to randomly change the phase of thecarrier every period of the transmission sequence, based on the controlsignal.

The bi-phasing PA may be configured to randomly change the phase of thecarrier between 0 degrees and 180 degrees every period of thetransmission sequence, based on the control signal.

The data encoder may be configured to encode the input data into pluralpredetermined sequence patterns, each encoded sequence patternrepresenting a different period of the transmission sequence.

The bi-phase controller may be configured to adjust the control signalso as to initiate plural phase changes of the carrier during a period ofthe transmission sequence.

The OOK transmitter may further include a first buffer configured tobuffer the carrier generated by the VCO, to reduce effects of thegenerated control signal on a frequency of the carrier, before thecarrier is provided to the bi-phasing PA.

The OOK transmitter may further include a second buffer configured tobuffer an output of the first buffer, to reduce effects of operations ofthe PA on the VCO, before the carrier is provided to the bi-phasing PA.

One or more embodiments provide an on-off keying (OOK) transmitterincluding a buffer configured to buffer a carrier, generated by avoltage-controlled oscillator (VCO), to reduce effects of operations ofa bi-phase power amplifier (PA) on the VCO, and the bi-phasing PAconfigured to randomly change a phase of the buffered carrier based on acontrol signal and to generate a transmission signal corresponding togenerated pulses, the pulses being generated based on a transmissionsequence obtained by an encoding of data.

The bi-phasing PA may be configured to randomly change the phase of thebuffered carrier between 0 degrees and 180 degrees every period of thetransmission sequence, based on the control signal.

One or more embodiments provide a communication method includingencoding input data into a transmission sequence, generating pulsesbased on the transmission sequence, generating a control signal tocontrol a random change in phase, between two phases, of a carrier basedon the transmission sequence, controlling a bi-phased switch to randomlychange a phase of the carrier based on the control signal, the carrierbeing generated by a voltage-controlled oscillator (VCO), and generatinga transmission signal based on the generated pulses and the carrier withthe randomly changed phase.

The controlling of the bi-phased switch to randomly change the phase ofthe carrier may include controlling the bi-phased switch to randomlychange the phase of the carrier between 0 degrees and 180 degrees atleast once every period of the transmission sequence, based on thecontrol signal, based on the control signal.

The communication method may further include buffering the carriergenerated by the VCO to reduce effects of the generated control signalon a frequency of the carrier.

One or more embodiments provide a communication method includingencoding input data into a transmission sequence, generating pulsesbased on the transmission sequence, generating a control signal tocontrol a random change in phase, between two phases, of a carrier basedon the transmission sequence, and controlling a bi-phasing poweramplifier (PA) to randomly change a phase of the carrier based on thecontrol signal and to generate a transmission signal based on thecarrier with the randomly changed phase and the generated pulses, thecarrier being generated by a voltage-controlled oscillator (VCO).

The controlling of the bi-phasing PA to randomly change the phase of thecarrier may include controlling the bi-phasing PA to randomly change thephase of the carrier between 0 degrees and 180 degrees at least onceevery period of the transmission sequence, based on the control signal.

The controlling of the bi-phasing PA to randomly change the phase of thecarrier may include controlling a bi-phased switch of the bi-phasing PAto perform the random changing of the phase of the carrier.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1D are block diagrams respectively illustrating anon-off keying (OOK) transmitter including a bi-phased switch, accordingto one or more embodiments.

FIGS. 2A and 2B are diagrams illustrating a bi-phased switch, accordingto one or more embodiments.

FIG. 3 is a timing diagram illustrating an operation of an OOKtransmitter, according to one or more embodiments.

FIG. 4 is a block diagram illustrating an OOK transmitter, according toone or more embodiments.

FIG. 5 is a block diagram illustrating an OOK transmitter including abi-phasing power amplifier (PA), according to one or more embodiments.

FIGS. 6A and 6B are diagrams illustrating a bi-phasing PA, according toone or more embodiments.

FIGS. 7A and 7B are diagrams illustrating example active signal paths ofthe bi-phasing PA of FIGS. 6A and 6B, according to one or moreembodiments.

FIGS. 8A and 8B are diagrams illustrating a bi-phasing PA, according toone or more embodiments.

FIGS. 9A and 9B are diagrams illustrating example active signal paths ofa bi-phasing PA, according to one or more embodiments.

FIG. 10 is a diagram illustrating an example of a simulation result of achange in a phase of a bi-phasing PA, according to one or moreembodiments.

FIG. 11 is a block diagram illustrating an OOK transmitter including abi-phasing PA, according to one or more embodiments.

FIG. 12 is a block diagram illustrating an OOK transmitter including afrequency error correction circuit, according to one or moreembodiments.

FIG. 13 is a diagram illustrating a coarse tuning circuit to correct afrequency error, according to one or more embodiments.

FIG. 14 is a timing diagram illustrating an example of an operation of acoarse tuning circuit, according to one or more embodiments.

FIGS. 15A and 15B are graphs provided to compare spectra obtained beforeand after a phase of a carrier is changed in an OOK transmitter,according to one or more embodiments.

FIG. 16 is a block diagram illustrating an OOK receiver, according toone or more embodiments.

FIG. 17 is a flowchart illustrating a communication method, according toone or more embodiments.

FIG. 18 is a flowchart illustrating a communication method, according toone or more embodiments.

Throughout the drawings and the detailed description, unless otherwisedescribed or provided, the same drawing reference numerals will beunderstood to refer to the same or like elements, features, andstructures. The drawings may not be to scale, and the relative size,proportions, and depiction of elements in the drawings may beexaggerated for clarity, illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, after an understanding of thepresent disclosure, various changes, modifications, and equivalents ofthe methods, apparatuses, and/or systems described herein will beapparent to one of ordinary skill in the art. The sequences ofoperations described herein are merely examples, and are not limited tothose set forth herein, but may be changed as will be apparent, after anunderstanding of the present disclosure, to one of ordinary skill in theart, with the exception of operations necessarily occurring in a certainorder. Also, descriptions of functions and constructions that may bewell known to one of ordinary skill in the art, after an understandingof the present disclosure, may be omitted for increased clarity andconciseness.

Various alterations and modifications may be made to embodiments, someof which will be illustrated in detail in the drawings and detaileddescription. However, it should be understood that these embodiments arenot construed as limited to the disclosure and illustrated forms andshould be understood to include all changes, equivalents, andalternatives within the idea and the technical scope of this disclosure.

Terms used herein are to merely explain specific embodiments, thus it isnot meant to be limiting. A singular expression includes a pluralexpression except when two expressions are contextually different fromeach other. For example, as used herein, the singular forms “a”, “an”,and “the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. Herein, a term “include” or “have”are also intended to indicate that characteristics, figures, operations,components, or elements disclosed on the specification or combinationsthereof exist. The term “include” or “have” should be understood so asnot to pre-exclude existence of one or more other characteristics,figures, operations, components, elements or combinations thereof oradditional possibility.

Unless otherwise defined, all terms including technical and scientificterms used herein have the same meaning as commonly understood by one ofordinary skill in the art to which respective embodiments belong. Itwill be further understood that terms, such as those defined incommonly-used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

When describing the examples with reference to the accompanyingdrawings, like reference numerals refer to like constituent elements anda repeated description related thereto will be omitted. When it isdetermined detailed description related to a related known function orconfiguration they may make a purpose of an embodiment unnecessarilyambiguous in describing the embodiment, such a detailed description willbe omitted.

FIGS. 1A through 1D are diagrams respectively illustrating an on-offkeying (OOK) transmitter 100 including a bi-phased switch 130, accordingto one or more embodiments.

Referring to FIG. 1A, the OOK transmitter 100 may include avoltage-controlled oscillator (VCO) 110, the bi-phased switch 130, apower amplifier (PA) 150, a data encoder 160, a bi-phase controller 170,and a pulse shaper 180, for example. The VCO 110 generates a carrier. Inother words, the VCO 110 outputs a radio frequency (RF) oscillationsignal corresponding to a carrier frequency.

The carrier generated by the VCO 110 may be OOK-modulated in the PA 150based on a signal in which data is encoded and that is received from thedata encoder 160 through the pulse shaper 180.

The bi-phased switch 130 may randomly change a phase of the carriergenerated by the VCO 110 based on a control signal generated by thebi-phase controller 170. The bi-phased switch 130 may randomly changethe phase of the carrier based on a unit of time of each element in atransmission sequence obtained through encoding, based on the controlsignal. In embodiments, the “unit of time of each element in thetransmission sequence” is understood to mean, for example, a timerequired to transmit an element “0” or “1” included in the sequence {0,1, 1, 0}, such as of a transmission sequence 320 corresponding to “0” indata 310 in FIG. 3, or a similar time representing the transmission timeof each element “0” or “1” in a particular sequence in the transmissionsequence 320. For example, the bi-phased switch 130 may implement therandom changes in phase so that any randomly implemented change occursin accordance with the periodicity of the elements of the transmissionsequence 320, e.g., so that a change in phase may occur at the same timeas a timed element transition in the transmission sequence 320, notingthat a period of the transmission sequence 320 may have a differentlength of time corresponding to the time between the beginning andending of each encoded bit sequences or symbols of the transmissionsequence 320, as only examples. For example, a bi-phased switch will bedescribed in greater detail with reference to FIGS. 2A and 2B.

To suppress a line spectrum, the bi-phased switch 130 may randomlychange the phase of the carrier by 0 degrees or 180 degrees in the unitof time of each element in the transmission sequence. An example inwhich the phase of the carrier output from the VCO 110 is randomlychanged by 0 degrees or 180 degrees by the bi-phased switch 130 isillustrated in FIG. 3. The bi-phased switch 130 is located between theVCO 110 and the PA 150. The OOK transmitter 100 randomly changes thephase of the carrier using the bi-phased switch 130, and performsbi-phasing so that the carrier has two phases, for example, 0 degreesand 180 degrees. The bi-phased switch 130 may randomly select either 0degrees or 180 degrees as the phase of the carrier based on the controlsignal generated by the bi-phase controller 170.

The PA 150 generates a transmission signal based on the carrier with thephase changed through the bi-phased switch 130 and a pulse generated bythe pulse shaper 180. The carrier, the pulse and the transmission signalmay correspond to, for example, an output 360 of a bi-phased switch, apulse 330, and a transmission signal 370 of an OOK transmitter of FIG.3, respectively. The PA 150 individually controls 15, for example, unitcells based on a signal received from the pulse shaper 180 to be poweredon or off, to perform an OOK modulation of the carrier.

The data encoder 160 encodes an input data sequence to a transmissionsequence using a conversion scheme provided in advance in acorresponding system. For example, the data encoder 160 may encode adata sequence provided in a digital baseband in a predetermined sequencepattern with digital values. In an example, the data encoder 160 mayencode an input data sequence of “1” to a transmission sequence of “1”without a change, and encode an input data sequence of “0” to atransmission sequence of “0” without a change. In another example, thedata encoder 160 may encode an input data sequence of “1” to atransmission sequence corresponding to [1,0,0,1], and encode an inputdata sequence of “0” to a transmission sequence corresponding to[0,1,1,0]. In still another example, when an input data sequenceincludes “M” elements, different transmission sequences, each including“L” elements, may be mapped to different input data sequences.

In above examples, in an embodiment, the data encoder 160 may use anelement selected from a set {−1, 0, 1} as an element of the transmissionsequence, which may correspond to ternary sequence spreading with threetypes of elements in a transmission sequence.

The bi-phase controller 170 may generate a control signal to randomlychange a phase of the carrier by one of two phases, for example 0degrees and 180 degrees, based on the transmission sequence output fromthe data encoder 160. A bi-phase shift by the control signal generatedby the bi-phase controller 170 may be implemented by synchronizationwith an output of the data encoder 160.

To enhance a spectrum efficiency, the pulse shaper 180 may generate apulse (for example, the pulse 330 of FIG. 3) corresponding to the inputdata (for example, the data 310 of FIG. 3) based on the transmissionsequence (for example, a transmission sequence 320 of FIG. 3) outputfrom the data encoder 160. The pulse generated by the pulse shaper 180may have, for example, a shape of a pulse quantized and implemented by adigital pulse shaping filter.

Referring to FIG. 1B, the OOK transmitter 100 may include a VCO 110, afirst buffer 120, a bi-phased switch 130, a PA 150, a data encoder 160,a bi-phase controller 170, and a pulse shaper 180. The first buffer 120is located between the VCO 110 and the bi-phased switch 130, forexample. The first buffer 120 buffers the carrier generated by the VCO110 and transfers the carrier to the bi-phased switch 130. The“buffering of the carrier” refers to a preventing, or implementedminimizing, of a frequency of the VCO 110 from being vibrated based onthe output or a control of the bi-phase controller 170.

In FIG. 1B, by adding the first buffer 120 between the VCO 110 and thebi-phased switch 130, it is possible to minimize a degradation in phasenoise occurring in the VCO 110 due to a bi-phasing operation of thebi-phased switch 130.

The first buffer 120 may minimize an impedance change shown in an outputof the VCO 110 by the bi-phased switch 130 and the PA 150, and therebymay minimize the degradation in the phase noise occurring in the VCO 110due to the bi-phasing operation.

Referring to FIG. 10, the OOK transmitter 100 may include a VCO 110, abi-phased switch 130, a second buffer 140, a PA 150, a data encoder 160,a bi-phase controller 170, and a pulse shaper 180, for example.

The second buffer 140 is located between the bi-phased switch 130 andthe PA 150. The second buffer 140 buffers the carrier with a phasechanged by the bi-phased switch 130, and transfers the carrier to the PA150. By adding the second buffer 340 in front of the PA 150, it ispossible to minimize an influence of phase noise occurring in thecarrier of the VCO 110 due to a pulse shaping operation of the pulseshaper 180.

The second buffer 140 may minimize the influence of the phase noiseoccurring in the carrier of the VCO 110 due to vibration of a loadimpedance of the VCO 110 due to a pulse shaping operation of the PA 150.

Referring to FIG. 1D, the OOK transmitter 100 may include a VCO 110, afirst buffer 120 (such as in FIG. 1B), a bi-phased switch 130, a secondbuffer 140 (such as in FIG. 10), a PA 150, a data encoder 160, abi-phase controller 170, and a pulse shaper 180, for example.

Accordingly, FIGS. 1B and 10 respectively demonstrate the abovedescribed first buffer 120 and second buffer 140 being usedindividually, while FIG. 1D demonstrates that the first buffer 120 andthe second buffer 140 may be used together, depending on embodiment,such as for desired power saving or other reasons.

In an example, a phase of a carrier may be randomly changed byperforming synchronization at a chip rate, and accordingly it ispossible to remove a harmonic spur occurring at a chip rate or ½ of thechip rate in an output waveform of the OOK transmitter 100. The chiprate is understood as a transmission rate, such as for the digitalsequence corresponding to an output of the data encoder 160.

FIGS. 2A and 2B are diagrams illustrating a bi-phased switch, accordingto one or more embodiments. As only examples, FIG. 2A illustrates anillustration symbol for the bi-phased switch and FIG. 2B illustrates anexample circuit represented by the illustration symbol for the bi-phasedswitch of FIG. 2A.

As only an example, the circuit of the bi-phased switch may include fourtransmission gates in total, for example, transmission gates 210, 220,230 and 240 of FIG. 2B. Among the four transmission gates, twotransmission gates, for example, the transmission gates 210 and 240 maybe used as signal paths for a phase setting of 0-degrees, i.e., a0-degree phase change, corresponding to an in-phase state, and the othertransmission gates, for example, transmission gates 220 and 230 may beused as signal paths for a phase setting of 180-degrees, i.e., an180-degree phase change, corresponding to an out-of-phase state. In thisexample, in each of the transmission gates 220 and 230, an illustratedpositive (+) terminal and a negative (−) terminal cross each other toselectively implement the phase change.

FIG. 3 is a timing diagram illustrating an operation of an OOKtransmitter, according to one or more embodiments.

FIG. 3 illustrates the data 310 that is input, the transmission sequence320, the pulse 330, a control signal 340, an input 350 of a bi-phasedswitch, the output 360 of the bi-phased switch, and the transmissionsignal 370 of the OOK transmitter, such as the OOK transmitter of any ofFIGS. 1A-1D. For example, the transmission sequence 320 may representdata encoded by the corresponding data encoder, the pulse 330 mayrepresent a pulse shaping code generated by a corresponding pulseshaper, the control signal 340 may represent a control signal generatedby a corresponding bi-phase controller, the input 350 may correspond toa carrier generated by a corresponding VCO, and the transmission signal370 may correspond to an output of a corresponding PA.

In this example, a single bit of the data 310 is encoded to thetransmission sequence 320 including four elements that have a value of“0” or “1.” For example, the “0” and “1” in the data 310 are encoded to“0110” and “1001” encoding symbols in the transmission sequence 320,respectively. Here, each example “0110” or “1001” of the transmissionsequence may respectively represent different periods of thetransmission sequence. The above encoding is an example of encoding ofOOK4 with a spreading factor of “4” performed by the data encoder,however, there is no limitation thereto, and embodiments are not limitedto the same. Accordingly, other encoding schemes may be used.

The pulse 330 is a pulse that is generated by the pulse shaper based onthe transmission sequence 320 to enhance a spectrum efficiency and thatcorresponds to the data 310. The pulse 330 has a shape of a quantizedpulse.

The control signal 340 is controlled, e.g., by the bi-phase controller,to randomly change between the two phase states, for example, theillustrated “+1” and “−1” in a same period of time as a period of thetransmission sequence 320. Here, the illustrated “+1” refers to a0-degree phase change corresponding to an in-phase state, and theillustrated “−1” refers to a 180-degree phase change corresponding to anout-of-phase state. As illustrated in FIG. 3, the timing of transitionsbetween elements in the transmission sequence 320 may be synchronizedwith the control signal 340, e.g., to synchronize when the changes inthe control signal 340 are randomly implemented to change the phase ofthe input 350 with a transition between elements in the transmissionsequence 320.

The input 350 corresponding to the carrier generated by the VCO, forexample, in FIGS. 1A-1D may be caused to become bi-phased to have twophases, for example, 0 degrees and 180 degrees through the bi-phasedswitch, as represented by the output 360 corresponding to either 0degrees or 180 degrees randomly being selected as a phase of the carrierbased on the control signal 340 generated by the bi-phase controller.

The output 360 is combined with the pulse 330 in the PA and is output asthe transmission signal 370. Thus, the carrier corresponding to theinput 350 may be modulated as a Gaussian pulse-shaped code based on thecontrol signal 340, similarly to the transmission signal 370. In anembodiment, a Gaussian pulse shape may be assumed, however, pulse shapesother than the Gaussian pulse shape may be used as a pulse code,similarly to an encoding scheme. In FIG. 3, changes in phases areindicated by dashed lines, and a dashed line oval 301 and a dashed linearrow 303 indicate phase changes from 0 degrees to 180 degrees.

FIG. 4 is a block diagram illustrating an OOK transmitter 400, accordingto one or more embodiments.

Referring to FIG. 4, the OOK transmitter 400 may include a VCO 410, abuffer 420, a PA 430, a data encoder 440, a bi-phase controller 450, apulse shaper 460, and a matching block 470, for example.

The VCO 410 generates a carrier. In other words, the VCO 410 may outputan RF oscillation signal corresponding to a carrier frequency.

The buffer 420 buffers the carrier generated by the VCO 410.

The PA 430 generates a transmission signal based on a control signalgenerated by the bi-phase controller 450 and a pulse generated by thepulse shaper 460.

The carrier generated by the VCO 410 is transferred to the PA 430through the buffer 420, the output of which is then transmitted to anOOK receiver via an antenna. The PA 430 may be controlled to be poweredon or off, to perform an OOK modulation of the carrier. The PA 430includes, for example, a plurality of (for example, N) digital PAs witha thermometer code or a binary code, to shape a pulse. For example, whenthe carrier is selectively output using the plurality of digital PAs, anamplitude of the PA 430 may have N states. In an example of a binarycode, the amplitude of the PA 430 may have 2N states.

The data encoder 440 encodes an input data sequence to a transmissionsequence using a predetermined conversion scheme. For example, the dataencoder 440 may encode a data sequence provided in a digital baseband ina preset sequence pattern with digital values. In an example, a pulseshaping code value obtained through M-fold oversampling of thetransmission sequence output from the data encoder 440 is converted to Nthermometer codes, and N digital PAs are individually controlled to bepowered on or off. The N digital PAs are, for example, PAs including Nbinary codes.

The bi-phase controller 450 generates the control signal to randomlychange a phase of the carrier by one of two phases, for example 0degrees and 180 degrees, based on the transmission sequence. Thegenerated control signal may be used to randomly change the phase of thecarrier in a unit of time of each element in the transmission sequenceoutput from the data encoder 440, to suppress a harmonic line spuroccurring in the OOK transmitter 400.

The pulse shaper 460 generates a pulse corresponding to the input databased on the transmission sequence output from the data encoder 440. Thetransmission sequence output from the data encoder 440 may beoversampled by a digital filter included in the pulse shaper 460 andconverted to a pulse shaping code.

The matching block 470 may perform impedance matching so that an outputpower of the PA 430 is transferred to the antenna with a minimum loss.

In accordance with an embodiment, a phase of a carrier in an RF regionmay be randomly changed by 0 degrees or 180 degrees during every, forexample, period of a transmission sequence (for example, for eachencoding symbol of the transmission sequence), and thus it is possibleto remove a line spectrum phenomenon, that is, a periodicity of a powerspectrum of a baseband symbol.

FIG. 5 illustrates an OOK transmitter 500 including a bi-phasing PA 530,according to one or more embodiments.

Referring to FIG. 5, the OOK transmitter 500 may include a VCO 410, abuffer 420, the bi-phasing PA 530, a data encoder 440, a bi-phasecontroller 450, and a pulse shaper 460, for example.

The bi-phasing PA 530 randomly changes a phase of an input carriergenerated by the VCO 410 based on a control signal, and generates atransmission signal corresponding to an input pulse. The bi-phasing PA530 randomly changes the phase of the carrier in a unit of time of eachelement in a transmission sequence obtained through encoding, based onthe control signal, and generates the transmission signal.

To suppress a line spectrum, the bi-phasing PA 530 randomly changes thephase of the carrier by 0 degrees or 180 degrees in the unit of time ofeach element in the transmission sequence, and generates thetransmission signal.

The bi-phasing PA 530 is controlled to be powered on or off, to performan OOK modulation of the carrier, and generates the transmission signal.As only an example, a more detailed description of such a bi-phasing PA530 is shown in FIGS. 6A and 6B, or 9A and 9B.

In addition, the description above regarding FIG. 4 is equallyapplicable to components other than the bi-phasing PA 530 in the OOKtransmitter 500, and accordingly such descriptions are not repeatedhere.

FIGS. 6A and 6B are diagrams illustrating a bi-phasing PA, according toone or more embodiments. As only examples, FIG. 6A illustrates anillustration symbol for a bi-phasing PA and FIG. 6B illustrates anexample circuit represented by the illustration symbol of the bi-phasingPA of FIG. 6A.

The bi-phasing PA is a PA that is configured to implement a shifting ofa phase of an output carrier by 0 degrees and 180 degrees, for example,based on a control signal (for example, a control signal from a bi-phasecontroller) applied by an external component or apparatus in acommunication device or system embodiment.

Referring to FIG. 6B, a control signal is generated by the bi-phasecontroller and applied to the bi-phasing PA (for example, theillustrated power amplifier Unit_PA[15:1] of FIG. 6A) at an encodingdata rate of 1 megahertz (MHz). The control signal is applied to a gateterminal of each of switching transistors M1, M2, M3 and M4 connected toa common source type of the bi-phasing PA. The control signal may be,for example, a phase shifting (PS) signal that is a switch controlsignal of “1” and “0.” The PS signal may be in an in-phase state or anout-of-phase state based on the control signal.

In an example, when the control signal is “1,” the switching transistorsM1[15:1] and M4[15:1] are turned on as a gain path of a signal. Inanother example, when the control signal is “0,” the switchingtransistors M5 and M8 are turned on as a gain path of a signal. Anactive signal path of a bi-phasing PA that may similarly operate basedon such a control signal is illustrated in FIGS. 7A and 7B. Here, theswitching transistors of the bi-phasing PA may be considered a bi-phasedswitch of the bi-phasing PA.

A thermometer code TMPA[15:1] for Gaussian pulse shaping may be appliedto a gate of each of transistors M10 and M11 of a cascode amplifier ofthe corresponding Unit_PA[15:1].

A TMPA signal may be applied to the bi-phasing PA at a sampling rate of6 MHz corresponding to six times a transmission sequence obtainedthrough encoding, for example, an encoding symbol. For a single Gaussianpulse, seven pieces of sampling data, for example, 1, 4, 9, 11, 9, 4 and1, may be applied.

As also illustrated in FIG. 6B, the signal produced by the bi-phasecontroller may be used to generate the In-phase control signal (orInphase) and an Out-of-phase (or Inphase_B) control signal.

FIGS. 7A and 7B are diagrams illustrating example active signal paths ofthe bi-phasing PA of FIGS. 6A and 6B, according to one or moreembodiments.

FIG. 7A illustrates an active signal path in an example in which an inphase signal Inphase is “1,” and FIG. 7B illustrates an active signalpath in an example in which an in phase signal Inphase is “0.” In anexample, when the Inphase signal is “1,” the Inphase_B signal may be “0”and a phase of an input signal may be the same as a phase of the outputsignal of the PA. In another example, when the Inphase signal is “0,”the Inphase_B signal may be “1” and the phase of the input signal andthe phase of the output signal may be reversed, or out of phase, by 180degrees.

FIGS. 8A and 8B are diagrams illustrating a bi-phasing PA, according toone or more embodiments. As only examples, FIG. 8A illustrates anillustration symbol of the bi-phasing PA and FIG. 8B illustrates anexample circuit represented by the illustration symbol of the bi-phasingPA of FIG. 8A. In FIGS. 8A and 8B, “Unit_PA [N:1]” is used to referencethe bi-phasing PA.

FIGS. 9A and 9B are diagrams illustrating example active signal paths ofthe bi-phasing PA of FIGS. 8A and 8B. Referring to FIG. 9A, when theInphase signal is “1,” the Inphase_B signal may be “0” and a phase of aninput signal of the PA may be the same as a phase of an output signal ofthe PA. Referring to FIG. 9B, when the Inphase signal is “0,” theInphase_B signal may be “1” and the phase of the input signal and thephase of the output signal may be reversed by 180 degrees.

FIG. 10 is a diagram illustrating an example of a simulation result of achange in a phase of a bi-phasing PA, according to one or moreembodiments.

As shown in the simulation result of FIG. 10, the phase of thebi-phasing PA is changed by 180 degrees based on the control signal,implanted through Inphase and Inphase_B signals. When an Inphase signalchanges from “1” to “0” or changes from “0” to “1,” a phase of a carrierinput PA_IN to the bi-phasing PA is reversed by 180 degrees and isoutput as PA_OUT.

FIG. 11 is a diagram illustrating an OOK transmitter 1100 including abi-phasing PA, such as the bi-phasing PA 530 of FIG. 5, according to oneor more embodiments.

Referring to FIG. 11, the OOK transmitter 1100 may include a VCO 410, athird buffer 1120, a fourth buffer 1130, the bi-phasing PA 530, a dataencoder 440, a bi-phase controller 450, and a pulse shaper 460, forexample. Here, though FIG. 11 will be described with reference to thebi-phase PA 530 of FIG. 5, this is only for convenience of descriptionand embodiments are not limited to the same.

The third buffer 1120 buffers a carrier generated by the VCO 410 andtransfers the buffered carrier to the fourth buffer 1130. The thirdbuffer 1120 may operate similarly to the first buffer 120 of FIGS. 1Band 1D.

The fourth buffer 1130 buffers an output of the third buffer 1120 andtransfers the output to the bi-phasing PA 530. In an embodiment, thefourth buffer 1130 may be used to minimize load pulling of the VCO 410due to the bi-phasing PA 530.

The above description of FIGS. 4 and 5 are equally applicable toremaining illustrated components other than the third buffer 1120 andthe fourth buffer 1130 in the OOK transmitter 1100, and accordinglydescriptions of the same are not repeated here.

Thus, in accordance with one or more embodiments, for example, the OOKtransmitter 1100 may be configured with the VCO 410, the third buffer1120 and the bi-phasing PA 530 among the components of FIG. 11. In thisexample, the third buffer 1120 may buffer the carrier generated by theVCO 410, and the bi-phasing PA 530 may randomly change a phase of thecarrier buffered by the third buffer 1120 based on a control signal andmay generate a transmission signal corresponding to an input pulse. Thepulse may be generated by the pulse shaper 460 based on a transmissionsequence obtained by encoding input data by the data encoder 440. Thebi-phasing PA 530 may randomly change the phase of the buffered carrierby 0 degree or 180 degrees in a unit of time of each element of thetransmission sequence, and may generate the transmission signal.

FIG. 12 is a block diagram illustrating an OOK transmitter 1200including a frequency error correction circuit, according to one or moreembodiments.

Referring to FIG. 12, the OOK transmitter 1200 may include a crystaloscillator (XO) 1205, a coarse tuner (CT) 1210, a VCO 1215, a buffer420, a PA 430, a matching block 470, a data encoder 440, a bi-phasecontroller 450, and a pulse shaper 460, for example.

In one or more embodiments, the VCO 1215, the buffer 420, the PA 430,the matching block 470, the data encoder 440, the bi-phase controller450, and the pulse shaper 460 may perform the same or similar operationsas the VCO 410, the buffer 420, the PA 430, the matching block 470, thedata encoder 440, the bi-phase controller 450, and the pulse shaper 460of FIG. 4, respectively, and accordingly further description thereof isnot repeated herein.

The XO 1205 may generate a reference frequency.

The CT 1210 may perform coarse tuning of an oscillation frequency of theVCO 1215. A coarse tuning scheme, e.g., of the CT 1210, will bedescribed in greater detail below with reference to FIG. 13. The XO1205, the CT 1210, and the VCO 1215 indicated by a dashed line box ofFIG. 12 may form or represent such a coarse tuning circuit of FIG. 13.

In accordance with one or more embodiments, an OOK receiver, such asthat discussed below with regard to FIG. 16, may be configured to detectan envelope during a demodulation of data because OOK modulation is usedby the example power amplifier 430. Accordingly, with OOK modulation,exact phase information of a carrier is not needed, and a receiver canhave a lower sensitivity to a frequency accuracy than that of thetransmitter.

In accordance with one or more embodiments, such an OOK transmitter andOOK receiver may operate using a coarse tuning scheme based on an on/offcycle, instead of continuously using a phase locked loop (PLL), forexample, with a relatively high amount of power to be consumed, based onthe above characteristics. The PLL may be used to control a frequency ofeach of a transmission carrier and a reception carrier based on theon/off cycle.

Also, the coarse tuning scheme may be used to tune frequencies ofmultiple channels.

In an embodiment, the CT 1210 may track a frequency using a 15-bitcapacitor bank (not shown), e.g., included in the VCO 1215, with a fineresolution. By using the 15-bit capacitor bank, it is possible toprevent a frequency drift from frequently occurring even though the CT1210 may be deactivated after a target channel frequency is locked.

In an example, before a transmission of a transmission signal occurs, afrequency is tuned using the CT 1210. During the transmission of thetransmission signal, a frequency synthesis may be performed based on aperiodic duty cycle to power off the CT 1210. By performing thefrequency synthesis based on the periodic duty cycle, power consumptiondue to the frequency synthesis in a PLL may be minimized.

FIG. 13 is a diagram illustrating a coarse tuning circuit to correct afrequency error, according to one or more embodiments.

Referring to FIG. 13, a CT 1330 may operate based on a periodic dutycycle.

When the CT 1330 receives channel information CH_SEL<4:0>, a mappingtable 1335 is used to convert the channel information to a correspondingreference channel code CH_REF<17:0>.

An oscillation frequency generated by a VCO 1350 may be divided by “2”by a divider 1331, which is then input to an 18-bit counter 1332. Anoutput VCO_CNT<17:0> of the 18-bit counter 1332 is compared to thereference channel code CH_REF<17:0> in a coarse tuning (CT) controller1333.

The CT controller 1333 transmits an up signal UP or a down signal DN toa tuning controller 1334 based on a comparison between the outputVCO_CNT<17:0> and the reference channel code CH_REF<17:0> and asuccessive approximation register (SAR) logic.

Through the above frequency tracking loop, Coarse Cap<9:0> and FineCap<4:0> of the VCO 1350 may be tuned based on a target frequency andlocked. A lock time and an accuracy of a tracking loop are traded offbased on an activation time of the 18-bit counter 1332. The 18-bitcounter 1332 is set by, for example, a signal EN_CNT with “1.”

The coarse tuning scheme may include two operations, for example, coarsetracking with an activation time of 120×REF_CLK and fine tracking withan activation time of 1000×REF_CLK.

A multiplexer (MUX) 1337 may select a coarse tracking control signalC_R<12:0> and a fine tracking control signal F_R<12:0> based on a signalC/F_MODE, and transmit the selected coarse tracking control signalC_R<12:0> and the selected fine tracking control signal F_R<12:0> to areference divider 1336.

In an embodiment, when frequency calibration is completed, almost allblocks in the CT 1330 except the tuning controller 1334 may be poweredoff. For example, the divider 1331, the 18-bit counter 1332, the CTcontroller 1333, the mapping table 1335, the reference divider 1336, andthe MUX 1337, indicated by a dashed line box of FIG. 13, are powered offafter frequency calibration is completed.

FIG. 14 is a timing diagram illustrating an example of an operation of acoarse tuning circuit, such as the coarse tuning circuit of FIG. 13,according to one or more embodiments. When a signal EN_CNT applied tothe 18-bit counter 1332 is high or “1,” the 18-bit counter 1332 startscounting. When the signal EN_CNT is low or “0,” a signal EN_COMP appliedto the CT controller 1333, a signal EN_CTUNE applied to the tuningcontroller 1334, and a reset signal RST_CNT applied to the 18-bitcounter 1332 are sequentially activated so that updating of a capacitorbank value and a comparing operation may be performed by the CTcontroller 1333 and that a reset operation may be performed by the18-bit counter 1332. The signals RST_CNT, EN_CNT, EN_COMP, and EN_CTUNEare obtained by the reference divider 1336 dividing a reference clockgenerated by an XO.

FIGS. 15A and 15B are graphs provided to compare spectra obtained beforeand after a phase of a carrier is changed in an OOK transmitter,according to one or more embodiments.

Referring to FIGS. 15A and 15B, when a phase of a carrier is randomlychanged through bi-phase switching or bi-phasing power amplification ata rate of 1 Mchip/sec, for example, line spurs shown at intervals of 1MHz disappear compared to a power amplification without phase changes.

In accordance with an embodiment, a bi-phased switch or bi-phasing PAperforms bi-phasing of a carrier, and thus it is possible to remove aharmonic spur in a transmission spectrum and to prevent spectrum maskmatching of an OOK transmitter and a reduction in a quality of atransmission signal.

FIG. 16 is a block diagram illustrating of an OOK receiver 1600,according to one or more embodiments.

Referring to FIG. 16, the OOK receiver 1600 may include an RF/analogblock 1610, an envelope detector 1620, an analog-to-digital converter(ADC) 1630, and a data decoder 1640, for example.

A signal received via an antenna is amplified by the RF/analog block1610, and an amplified modulated carrier is demodulated to a basebandsignal by the envelope detector 1620.

Because the envelope detector 1620 demodulates the signal using a squareoperation, bi-phasing inserted to remove line spurs does not have aninfluence on the demodulating. A signal digitized by the ADC 1630 (or acomparator), may be recovered as a data sequence by the data decoder1640.

As described above, the OOK receiver 1600 demodulates the signal throughenvelope detection, and accordingly randomly changing of a phase of acarrier every period of a transmission sequence obtained throughencoding may not have an influence on a demodulation process.

FIG. 17 is a flowchart illustrating a communication method, according toone or more embodiments.

Referring to FIG. 17, in operation 1710, a transmitter encodes inputdata in the form of a transmission sequence.

In operation 1720, the transmitter generates a pulse corresponding tothe input data based on the transmission sequence.

In operation 1730, the transmitter generates a control signal torandomly change a phase by one of two phases in a unit of time of eachelement in the transmission sequence.

In operation 1740, the transmitter randomly changes a phase of a carriergenerated by a VCO, based on the control signal. The transmitterrandomly changes the phase of the carrier by 0 degrees or 180 degrees ina unit of time of each element in the transmission sequence, based onthe control signal.

In operation 1750, the transmitter generates a transmission signal basedon the pulse generated in operation 1720 and the carrier with the phasechanged in operation 1740.

In an example, the transmitter buffers the carrier generated by the VCO,and performs operation 1740. In another example, the transmitter buffersthe carrier having the phase changed in operation 1740, and performsoperation 1750.

FIG. 18 is a flowchart illustrating a communication method, according toone or more embodiments.

Referring to FIG. 18, in operation 1810, a transmitter encodes inputdata in the form of a transmission sequence.

In operation 1820, the transmitter generates a pulse corresponding tothe input data based on the transmission sequence.

In operation 1830, the transmitter generates a control signal based onthe transmission sequence. The control signal is used to randomly changea phase by one of two phases.

In operation 1840, the transmitter randomly changes a phase of a carriergenerated by a VCO based on the control signal generated in operation1830, and generates a transmission signal corresponding to the pulse. Inoperation 1840, the transmitter randomly changes the phase of thecarrier by 0 degrees or 180 degrees in a unit of time of each element inthe transmission sequence based on the control signal, and generates thetransmission signal.

Below, though aspects of the methods of FIGS. 17 and 18 have beendescribed with regard to a transmitter, embodiments are not limited tothe same, and the described operations may be implemented by anothercommunication device or system. With further regard to FIGS. 17 and 18,any of the above description of operations of FIGS. 1A through 15B areequally applicable to, and depending on embodiment similarly representedby, the communication methods of FIGS. 17 and 18. Accordingly, suchabove descriptions have not been repeated in the discussion of FIGS. 17and 18. An embodiment of the present disclosure similarly includes acommunication method represented by the receiver description of FIG. 16,so that such descriptions are similarly not repeated here.

In addition to the elements of FIGS. 1A-2, 4-9B, 11-13, and 16 beinghardware elements or components, the methods of FIGS. 17 and 18 may beimplemented by hardware components, including the above discussedexample hardware elements and/or one or more processing devices, orprocessors, or computers, and the elements or components of FIGS. 1A-2,4-9B, 11-13, and 16 may similarly be included in an electronic deviceembodiment as hardware components thereof. Hardware components mayinclude, as only examples, resistors, transistors, capacitors,inductors, power supplies, controllers, frequency generators,operational amplifiers, power amplifiers, low-pass filters, high-passfilters, band-pass filters, analog-to-digital converters,digital-to-analog converters, and processing device(s), processor(s),and/or computer(s), as only examples. A processing device, processor, orcomputer may be implemented by one or more processing elements, such asan array of logic gates, a controller and an arithmetic logic unit, adigital signal processor, a microcomputer, a programmable logiccontroller, a field-programmable gate array, a programmable logic array,a microprocessor, or any other device or combination of devices known toone of ordinary skill in the art that is capable of responding to andexecuting instructions in a defined manner to achieve a desired result.In one example, a processing device, processor, or computer includes, oris connected to, one or more memories storing instructions or softwarethat are executed by the processing device, processor, or computer andthat may control the processing device, processor, or computer toimplement one or more methods described herein. Hardware componentsimplemented by a processing device, processor, or computer may executeinstructions or software, such as an operating system (OS) and one ormore software applications that run on the OS, to perform or control oneor more of the operations described herein with respect to FIGS. 17 and18, for example. The hardware components also access, manipulate,process, create, and/or store data in response to execution of theinstructions or software. For simplicity, the singular term “processingdevice”, “processor”, or “computer” may be used in the description ofthe examples described herein, but in other examples multiple processingdevices, processors, or computers are used, or a processing device,processor, or computer includes multiple processing elements, ormultiple types of processing elements, or both. In one example, ahardware component includes multiple processors, and in another example,a hardware component includes a processor and a controller. A hardwarecomponent has any one or more of different processing configurations,examples of which include a single processor, independent processors,parallel processors, remote processing environments, single-instructionsingle-data (SISD) multiprocessing, single-instruction multiple-data(SIMD) multiprocessing, multiple-instruction single-data (MISD)multiprocessing, and multiple-instruction multiple-data (MIMD)multiprocessing, as only examples.

The methods illustrated in FIGS. 17 and 18 that perform or control theoperations described herein may be performed or controlled by aprocessing device, processor, or a computer as described above executinginstructions or software to perform one or more of the operationsdescribed herein.

Instructions or software to control a processing device, processor, orcomputer to implement the hardware components and perform the methods asdescribed above may be written as computer programs, code segments,instructions or any combination thereof, for individually orcollectively instructing or configuring the processing device,processor, or computer to operate as a machine or special-purposecomputer to perform the operations performed by the hardware componentsand the methods as described above. In one example, the instructions orsoftware include machine code that is directly executed by theprocessing device, processor, or computer, such as machine code producedby a compiler. In another example, the instructions or software includehigher-level code that is executed by the processing device, processor,or computer using an interpreter. Based on the disclosure herein, andafter an understanding of the same, programmers of ordinary skill in theart may readily write the instructions or software based on the blockdiagrams and the flow charts illustrated in the drawings and thecorresponding descriptions in the specification, which disclose suchmethod operations and which may be performed or implemented by any ofthe above described hardware components, for example.

The instructions or software to control a processing device, processor,or computer to implement the hardware components, such as discussed inany of FIGS. 1A-2, 4-9B, 11-13, and 16 and perform or control theimplementation of the methods as described above in FIGS. 17 and 18, andany associated data, data files, and data structures, are recorded,stored, or fixed in or on one or more non-transitory computer-readablestorage media. Examples of a non-transitory computer-readable storagemedium include read-only memory (ROM), random-access memory (RAM),dynamic random-access memory (D-RAM), static random-access memory(S-DRAM), flash memory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs, DVD-ROMs,DVD-Rs, DVD+Rs, DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs,BD-REs, magnetic tapes, floppy disks, magneto-optical data storagedevices, optical data storage devices, hard disks, solid-state disks,and any device known to one of ordinary skill in the art that is capableof storing the instructions or software and any associated data, datafiles, and data structures in a non-transitory manner and providing theinstructions or software and any associated data, data files, and datastructures to a processing device, processor, or computer so that theprocessing device, processor, or computer can execute the instructions.In one example, the instructions or software and any associated data,data files, and data structures are distributed over network-coupledcomputer systems so that the instructions and software and anyassociated data, data files, and data structures are stored, accessed,and executed in a distributed fashion by the processing device,processor, or computer.

As a non-exhaustive example only, and in addition to the aboveexplanation of potential hardware implementations of the electronicdevice, an electronic device embodiment herein, such as an electronicdevice embodiment that includes any of the communication devices ofFIGS. 1A-2, 4-9B, 11-13, and 16, as only an example, may also be amobile device, such as a cellular phone, a smart phone, a wearable smartor bio-signal device, a portable personal computer (PC) (such as alaptop, a notebook, a subnotebook, a netbook, or an ultra-mobile PC(UMPC), a tablet PC (tablet), a phablet, a personal digital assistant(PDA), a digital camera, a portable game console, an MP3 player, aportable/personal multimedia player (PMP), a handheld e-book, a globalpositioning system (GPS) navigation device, or a sensor, or a stationarydevice, such as a desktop PC, a television or display, a DVD player, aBlu-ray player, a set-top box, or a home appliance, an Internet ofThings device, or any other mobile or stationary device, e.g., capableof wireless or network communication. As only an example, thecommunication device may be a device that transmits data according to aWBAN protocol.

While this disclosure includes specific examples, it will be apparent toone of ordinary skill in the art that various changes in form anddetails may be made in these examples without departing from the spiritand scope of the claims and their equivalents. The examples describedherein are to be considered in a descriptive sense only, and not forpurposes of limitation. Descriptions of features or aspects in eachexample are to be considered as being applicable to similar features oraspects in other examples. Suitable results may be achieved if thedescribed techniques are performed in a different order, and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner, and/or replaced or supplemented by othercomponents or their equivalents. Therefore, the scope of the disclosureis not limited by the detailed description, but further supported by theclaims and their equivalents, and all variations within the scope of theclaims and their equivalents are to be construed as being included inthe disclosure.

What is claimed is:
 1. An on-off keying (OOK) transmitter comprising: abuffer configured to buffer a carrier, generated by a voltage-controlledoscillator (VCO), to reduce effects of operations of a bi-phase poweramplifier (PA) on the VCO; and the bi-phasing PA configured to randomlychange a phase of the buffered carrier based on a control signal and togenerate a transmission signal corresponding to generated pulses, thepulses being generated based on a transmission sequence obtained by anencoding of data.
 2. The OOK transmitter of claim 1, wherein thebi-phasing PA is configured to randomly change the phase of the bufferedcarrier between 0 degrees and 180 degrees every period of thetransmission sequence, based on the control signal.